A gaming app developed for vestibular rehabilitation improves the accuracy of performance and engagement with exercises.

Introduction: Vestibular hypofunction is associated with dizziness, imbalance, and blurred vision with head movement. Vestibular rehabilitation is the gold standard recommendation to decrease symptoms and improve postural stability. The Clinical Practice Guidelines for vestibular hypofunction suggest home exercises 3-5 times daily, but patient adherence is a problem, with compliance rates often below 50%. Methods: An app was developed to increase engagement with home exercises by providing exercises as games. This study compared the accuracy of exercise performance in a one-time session using the app versus no-app and gathered participant feedback on using the app for vestibulo-ocular reflex (VOR) and balance exercises. The app was tested with 40 adults (20 women), mean age of 67 ± 5.7 years, with symptomatic unilateral or bilateral vestibular hypofunction. Participants completed VOR exercises in pitch and yaw planes, weight-shift, and single-leg balance exercises using an inertial motion unit to move the character on the tablet screen. Participants were randomly assigned to begin the exercises with or without the app. Results: Results show that during VOR exercises, participants achieved the prescribed frequency of head motion for the yaw plane (p ≤ 0.001) and reduced variability of head movement frequency in both the yaw (p ≤ 0.001) and pitch plane (p ≤ 0.001) in the app compared to the no-app condition. During weight-shifting exercises, a larger range of body motion was noted in the anteroposterior and mediolateral directions in the app compared to the no-app condition (p < 0.05). During single-leg balance exercises, pelvic motion was lower in the app versus no-app condition (p = 0.02). Participants modified their exercise performance and corrected their mistakes to a greater extent when they used the app during the VOR exercises. Participants agreed that they felt motivated while playing the games (97%) and felt motivated by the trophies (92%). They agreed that the app would help them perform the exercises at home (95%), improve their rehab performance (95%) and that it was fun to do the exercises using the app (93%). Discussion: The results of this study show that technology that is interactive and provides feedback can be used to increase accuracy and engagement with exercises.

Automated optimization of residual reduction algorithm parameters in OpenSim.

The residual reduction algorithm (RRA) in OpenSim is designed to improve dynamic consistency of kinematics and ground reaction forces in movement simulations of musculoskeletal models. RRA requires the user to select numerous tracking weights for the joint kinematics to reduce residual errors. Selection is often performed manually, which can be time-consuming and is unlikely to yield optimal tracking weights. A multi-heuristic optimization algorithm was used to expedite tracking weight decision making to reduce residual errors. This method produced more rigorous results than manual iterations and although the total computation time was not significantly reduced, this method does not require the user to monitor the algorithm's progress to find a solution, thereby reducing manual tuning. Supporting documentation and code to implement this optimization is freely provided to assist the community with developing movement simulations.

Use of Stakeholder Feedback to Develop an App for Vestibular Rehabilitation-Input From Clinicians and Healthy Older Adults.

Close to half people over 60 years of age experience vestibular dysfunction. Although vestibular rehabilitation has been proven effective in reducing dizziness and falls in older adults, adherence to exercise programs is a major issue and reported to be below 50%. Therefore, this research aimed to develop an app with gaming elements to improve adherence to exercises that are part of vestibular rehabilitation, and to provide feedback to increase the accuracy during exercise performance. A clinician-informed design was used where five physical therapists were asked identical questions about the exercises they would like to see in the app, including their duration and frequency. Games were developed to train the vestibulo-ocular (VOR) reflex using VOR and gaze shifting exercises; and to train the vestibulo-spinal system using weight shifting and balance exercises. The games were designed to progress from simple to more complex visuals. The games were controlled by an Inertial Measurement Unit placed on the head or anterior waist. The app was tested on ten healthy females (69.1 ± 5.1 years) with no prior history of vestibular dysfunction or complaints of dizziness. Participants completed gaze stabilization and balance exercises using the app and provided feedback on the user interface, ease of use, usefulness and enjoyment using standardized questionnaires and changes they would like to see in the form of open-ended questions. In general, participants reported that they found the app easy to use, the user interface was friendly, and they enjoyed playing the games due to the graphics and colors. They reported that the feedback provided during the exercise session helped them recognize their mistakes and motivated them to do better. However, some elements of the app were frustrating due to incomplete instructions and inability to distinguish game objects due to insufficient contrast. Feedback received will be implemented in a revised version which will be trialed in older adults with dizziness due to vestibular hypofunction. We have demonstrated that the "Vestibular AppTM" created for rehabilitation with gaming elements was found to be enjoyable, useful, and easy to use by healthy older adults. In the long term, the app may increase adherence to vestibular rehabilitation.

Automated medical avatar animation for warfighter mission simulation.

BACKGROUND: Virtual representations of human internal anatomy are important for military applications such as protective equipment design, injury severity prediction, thermal analysis, and physiological simulations. High-fidelity volumetric models based on imaging data are typically in static postures and difficult to use in simulations of realistic mission scenarios. This study aimed to investigate a hybrid approach to reposition medical avatars that preserves internal anatomy but allows rapid repositioning of full three-dimensional (3D) meshes. METHODS: A software framework that accepts a medical avatar in a 3D tetrahedral mesh format representing 72 organs and tissues with an articulated skeleton was developed. The skeleton is automatically resized and associated to the avatar using rigging and skinning algorithms inspired by computer animation techniques. Military relevant motions were used for animations. A motion retargeting algorithm was implemented to apply animation to avatars of various sizes, and a motion blending algorithm was implemented to smoothly transition between movements. These algorithms were incorporated into a path generation tool that accepts initial, intermediate, and final coordinates of a multisegment action along with the specific motion for each segment to synthesize a realistic compound set of movements comprising the animation. RESULTS: The developed pipeline for dynamic repositioning of medical avatars was demonstrated. Various complex motions were automatically animated. Retargeting was demonstrated on models of varying sizes. Movements along a path were animated to demonstrate smooth motion transitions. Animation of the full 3D avatar mesh ran in real time on a standard desktop personal computer. The repositioning algorithm successfully preserved the shape and volume of rigid structures such as bone. CONCLUSION: The developed software leverages techniques from various disciplines to create a hybrid approach enabling real-time 3D mesh repositioning appropriate for use in simulated military missions using avatars containing a complete anatomy representation. The workflow is largely automated, enabling rapid evaluation of new mission scenarios.